U.S. President Barack Obama is commuting the prison sentences of 61 people serving time for drug-related crimes.

The White House says more than one-third of the inmates were serving life sentences. All of them were jailed for drug possession, intent to distribute or related crimes. A few also had firearms violations.

In a letter to those receiving clemency, Obama said the power to grant pardons and commutations "embodies the basic belief in our democracy that people deserve a second chance after having made a mistake in their lives that led to a conviction under our laws."

The White House says Obama also cautioned those receiving clemency that what they do with this unexpected opportunity reflects not only on each individual person, but also on all those still behind bars who are seeking that same shot at a new life.

Deputy Attorney General Sally Yates said the president's announcement "demonstrates his commitment to ensuring a fair and just criminal justice system."

"The clemency initiative that the President announced in 2014 is an important part of the department’s overall criminal justice reform efforts," Yates said in a Department of Justice statement. "We hope to soon realize systemic change in the length of prison sentences for these low-level drug offenders and to provide better tools for a safe and successful reentry into the community."

The White House says Obama has now commuted the sentences of 248 individuals – more than the last six presidents combined.